Scientific Linux Security Update : sendmail on SL4.x i386/x86_64
High Nessus Plugin ID 60962
SynopsisThe remote Scientific Linux host is missing one or more security updates.
DescriptionA flaw was found in the way sendmail handled NUL characters in the CommonName field of X.509 certificates. An attacker able to get a carefully-crafted certificate signed by a trusted Certificate Authority could trick sendmail into accepting it by mistake, allowing the attacker to perform a man-in-the-middle attack or bypass intended client certificate authentication. (CVE-2009-4565)
The CVE-2009-4565 issue only affected configurations using TLS with certificate verification and CommonName checking enabled, which is not a typical configuration.
This update also fixes the following bugs :
- Previously, sendmail did not correctly handle mail messages that had a long first header line. A line with more than 2048 characters was split, causing the part of the line exceeding the limit, as well as all of the following mail headers, to be incorrectly handled as the message body. (BZ#499450)
- When an SMTP-sender is sending mail data to sendmail, it may spool that data to a file in the mail queue. It was found that, if the SMTP-sender stopped sending data and a timeout occurred, the file may have been left stalled in the mail queue, instead of being deleted. This update may not correct this issue for every situation and configuration. Refer to the Notes section for further information. (BZ#434645)
- Previously, the sendmail macro MAXHOSTNAMELEN used 64 characters as the limit for the hostname length.
However, in some cases, it was used against an FQDN length, which has a maximum length of 255 characters.
With this update, the MAXHOSTNAMELEN limit has been changed to 255. (BZ#485380)
After installing this update, sendmail will be restarted automatically.
Notes: As part of the fix for BZ#434645, a script called purge-mqueue is shipped with this update. It is located in the /usr/share/sendmail/ directory. The primary purpose of this script is a one-time clean up of the mqueue from stalled files that were created before the installation of this update. By default, the script removes all files from /var/spool/mqueue/ that have an atime older than one month. It requires the tmpwatch package to be installed. If you have stalled files in your mqueue you can run this script or clean them manually.
It is also possible to use this script as a cron job (for example, by copying it to /etc/cron.daily/), but it should not be needed in most cases, because this update should prevent the creation of new stalled files.
SolutionUpdate the affected packages.